For a variety of purposes including recreation, medical therapy and survival, it is desirable to provide devices for assisting humans in personal flotation. Various known personal flotation devices exist, most typically in the form of a vest or jacket-type flotation device worn like a garment or a flotation ring.
The jacket-type flotation device is worn securely around the torso of the body and, generally, causes the body to float in a substantially vertical position, whereby the head is above the surface of the water and the feet and legs are extended downward. While this design has some advantages over others because it can be securely fastened to a body, and remain securely fastened, before and after entry into water, it limits flotation to the substantially vertical position and it necessarily covers around the body. In recreational or therapeutic situations, a horizontal floating position may be desired or required. Additionally, in survival or rescue situations, it may be desirable to maintain a person's body in a horizontal situation if, for example, the person is in shock or has been traumatized. To some extent, a person's body temperature can be maintained for a longer period of time in otherwise cold waters if the body horizontally and as close to the surface as possible. In certain situations, such as when one is sun-tanning or relaxing, or when one has been injured in the torso area, it may be undesirable to wear a wrap-around flotation jacket. For these and other reasons, a vest or jacket-type flotation device has shortcomings.
Conventional flotation rings, usually made of foam or inflatable plastic, are designed to be grasped and held by a person's hand or, in the case of a child's recreation device, worn around the torso and under the arms. In either context, the flotation ring requires the person using it to be floated in a semi-horizontal position. It is difficult to sit on such a flotation ring without, due to difficulty in balance, slipping off the ring to one side and having the ring come shooting up to the surface of the water. The exception is the use of an over-sized tire inner type in which a person can sit with his seat positioned in the center of the tube. In this situation, however, the person is elevated above the water and does not experience or obtain the benefit and enjoyment of submersion in the water. Nor does the person have the ability to stretch out or moved his arms and legs, while submerged, for comfort, exercise and therapy.
The least buoyant part of the human body is the lower half, since it generally contains more dense mass than the upper half. Thus, in order to support a human body in floating equilibrium, it is necessary to compensate for this buoyancy imbalance by providing buoyant lift to the lower half of the body. Certain devices, such as conventional inflatable rafts and floating chairs provide buoyant lift to the lower half of the body.
Conventional inflatable rafts or mattresses, while permitting a person to float horizontally, do not enable submersion into the water. Other known devices, such as floating garden chairs and the like are cumbersome and restrict movement. In addition, they typically require the upper part of the body to remain out of the water, thereby eliminating the cooling effect of the water on that part of the body.